High-speed hydraulic press



Dec. 20, I927. W. ERNST HIGH SPEED HYDRAULIC PRESS Filed March 15, 1927 2 Sheets-Sheet l awn tor WZlli'er Errwb Dec. 20, 1927.

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UNITED STATES PATENT OFFICE.

WALTER ERNST, OF MOUNT GILEAD, OHIO, ASSIGNOR TO THE HYDRAULIC'PRESS MANUFACTURING COMPANY, OF MOUNT GILEAD, OHIO.

HIGH-SPEED HYDRAULIC PRESS.

Application filed March 15, 1927. Serial No. 175,588.

This invention relates to hydraulic presses which are intended to be operated by fluid supplied under pressure from a revers ble variable delivery pump and has for an ()l) ](('l) the provision of simple and cflicient valve mechanism by which the proper sequence of operations will be carried out automatically or semi-automati ally. Detail i'eatures oi the invention will be apparent from the fol-- lowing description and the appended claims.

This invention is in the nature of an improvement upon my copending application Serial No. 138.416, filed September 29, 1926.

In the drawings:

Figure 1 is a side elevation of one type of press having embodied therein the presentinvention.

Figure 2 is a side elevation taken at right angles to Figure 1.

Figure 3 is a diagrammatic view with certain valve mechanism shown in section and indicating the various connections from the pump to the operating mechanism of the press.

Figure 4 is a section through a modlfied form of valve.

The invention may be embodied in various types of presses employed for various purposes, but is illustrated 1n connection with a press of the four column downward pressure type. There is shown a base A which may be formed of cast iron for the purpose of bringing the working surface to a convenient height. Above thls 1s a heavy cast steel base 13 which receives the strains from the press. A press head C 1s connected to the base by four strain rods The main downwardly movable platen E guided on the strain rods in the usual man ner. 'There is also illustrated in Figure 1 a variable delivery reversible pump F and connections for operating the same which form no part of the present invention.

A pipe line 1 is shown as leading from the pump and has a branch 2 whlch communicates with two booster cylinders 3 which are intended to initiate the movement of the press ram. This line also has a connect on 4 leading to a valve mechanism generally 1ndicated at 5. From this valve mechanism a pipe 6 communicates with the main cylinder 7 above the press ram. From the upper part of this cylinder a pipe 8 communicates by the way of a valve mechanism indicated generally at 9 with a surge tank 10 which has an outlet pipe 11..

A second pipe 12 leads from the pump F and has a separate branch 13 communicating with the two push back cylinders 14 which return the platen to its upper position. This line 12 also has a line 15 which communicates with a small chamber underlying the stem of the valve mounted in the valve mechanism 9 above mentioned.

The pipe 1 also communicates with a chamber 16 and the pipe 12 with a similar chamber 17 in a valve casing 18 which has a central chamber 19 that communicates with both chambers 16 and 17. The communication between the chambers 16 and 19 is controlled by a valve 20 and the communication between the chambers 17 and 19 is controlled by a valve 21 both of which valves are carried by a valve stem 22 of such length that when one communication is open the other is closed. tank also communicates with the chamber 19.

The pipe 12 has a branch 23 leading to a safety valve 24 and the pipe 1 has a similar branch 25 leading to a safety valve 26, these valves being of old and well known construction and forming in themselves no part of the present invention. The outlet pipe 11 from the surge tank 10 has a branch 27 communicating with the safety valves.

The valve mechanism 9 comprises a casing 28 having a passage 29 therein which is controlled by a valve 30. The stem 31 of this valve is separate and fits slidably at its lower end in a short tubular member 32 which is connected to the end of the pipe 15 and has suitable packing 33 and a chamber 34 into which the free end of the valve stem extends. A coil spring 35 surrounds the valve stem 31 and bears at its lower end against a collar 36 carried by the valve stem and at its upper end against a fixed collar 37 through which the valve stem slides so that this spring tends to hold the stem 31 in its lower position in which the valve 30 will close by gravity.

The valve mechanism 5 comprises a casing 38 having a passage 39 therein which is closed by a valve 40. The valve stem 41 is separate from the valve and extends downward through suitable packing 42 to the outside of the valve casing. lower end it has an enlargement 43 against The pipe 11 leading from the surge At its one side of which bears a spring 44 which is coiled around the valve stem and at its other end bears against the outside of the casing. This enlar ement 43 also bears against one end of a fever 45 pivoted at 46 and connected at its other end to a rod 47. The rod as sh wn in Figure 1 extends downward through a boss 48 on the platen head and near its lower end is provided with an adjustable stop collar 30 provided with a spring 50 on its upper side.'

The operation of the device may be described as follows: It is assumed that 1t s desired to operatethe ress. The pump is set to deliver fluid un er pressure through the line 1. The branch of this line which communicates with the chamber 16 will permit the fluid under pressure to pass into sa1d chamber and contact with the valve 20, thus moving the same toward the right of Figure 3 so that communication is closed between the line 1 and the pipe 11 which communicates with the surge tank. At the same time fluid under pressure will pass throu h the branch pipe line 2 to the booster cy inders 3 and start the movement of the press ram downward. This, of course, tends to produce a vacuum in the upper portion of the main cylinder but the suction exerted through the pipe 8 will lift the valve 30 off its seat against the force of gravity and of spring 35 and permit liquid to flow from the surge tank 10 through valve casing 9 and li pe 8 into the upper port-ion of the main cy inder behind the press ram. This action will continue until the platen in its downward movement reaches a predetermined point, when the boss 48 will contact with the spring 50 and through the stop collar 49 move the rod 47 downward and through the lever 45 push the valve stem 41 upward and open the valve 40. This will admit fluid from the main line 1 through the branch 4, passage 39, and pipe 6 to the cylinder 7. AS soon as this fluid which is under high pressure enters the main cylinder 7, the back pressure exerted through the pipe 8 will close the valve 30 and prevent the fluid from returning to the surge tank at this time. The parts will remain in this position until the pressing operation is completed. Thereafter either automatically or manually the pump will be reversed and will discharge fluid under pressure into the pipe line 12. The branch 13 of. this line will conduct fluid to the push back cylinders 14 and immediately begin returning the ram to its normal upper position. At the same time the fluid which enters through the branch line into the chamber 17 of the valve casing 18 will contact with the valve 21 and move thesame to the left, thus closin communication between the pipe 12 an the line 11 which leads to the surge tank. At the same time the fluid under pressure will pass under the branch line 15 into the chamber 34 and move the valve stem 31 upward, lifting the valve 30, 01! of its seat and permitting the fluid above the press ram which is now movmg n wardly to be forced through the pipe 8 an valve chamber 9 into the surge tank 10. As soon as the press ram reaches its upper normal position, it will be stopped automatically.

It is to be noted that durin movement the booster rams wil also be moving upward in the booster cylinders 3 and the fluid contained in these cylinders will be forced through the ipe line 2 into the main line 1 and thence eit er back to the ump or through the chambers 16 and 19 and pipe 11 to the surge tank 10.

Instead of using the mechanical means 'ust described for shifting the delivery of uid from the pump to the main -c linder instead of the booster cylinders which is brought about by opening the valve 40, this valve may be operated b pressure as in theconstruction illustrated in Figure 4. The valve casing and valve are the same as in Figure 3 but in this form the valve stem 41 rests upon a lever 51 pivoted at 52 to a bracket.

The spring 53 bears against one end of the lever and against the bracket member and normally tends to force the lever 51 upward, thereby actuating the valve stem 41 and opening the valve 40. This action is prevented by means of a lever 55 pivoted at 56 to the bracket 54 and having a hook end 57 which overlies the lever 51 and prevents its movement under the influence of the spring 53.

The lower end of the lever 55 is engaged by one end of a coil spring 58, the other end of which bears against a member 59 that may be adjusted by manual means 60 to tension the spring. This spring 58 tends to hold the lever in such position that the hook is operated to retain the lever 51 and allow the valve 40 to remain closed.

The casing 61 which may be carried by the bracket 54' has a chamber 62 therein connected by a pipe 63 to the pump .line. The pressure in this chamber 18 therefore the same as that in the pump line 1. The differential piston 64 is slidably mounted in the casing 61 and has one end extending into the chamber 62. A rod connected to the piston 64 is' pivoted at 65 to the lever 55. A suitable packing is employed for' both the piston 64 and the attached rod.

The operation of this form of the device is as follows. When the valve 4 is closed, pressure will build up in the pipe line 1 and a connected line 63 until the pressure in the chamber 62 is suflicient to move the piston 64 and the lever 55 against the tension of the spring 58. This will move the book 57 to the right in Figure 4 and release lever 51 which will move the valve stem 41 upward and open the valve 40. On the return this return movement of the press platen a boss similar to the boss 48 will engage a collar on a rod 66 connected to the upper end of the lever 51 and positioned so that this rod will be operated near the end of the upward movement of the platen. This will move the right hand end of the lever 51 downward and permit the lever 55 to move to locking position. This movement will be brought about by the spring 58 since the pressure in the chamber 62 is now released. It will be noted that the right hand end of the lever 51 has a downward extension 67 against which the end of the hook 57 engages when released from the upper side of the lever. This permits the return movement of the lever 51 just described.

The pump employed is of the rotary reversible variable delivery type and may be controlled by mechanism such as shown in applicants copending application Serial No. 153,410 filed December 8, 1926. Any equivalent mechanism may, however, be employed for this purpose if desired. In general it is to be understood that the invention is to be regarded as limited only by the scope of the appended claims.

I claim as my invention:

1. In a hydraulic press mechanism having main, booster and push-back cylinders, a press ram operated thereby and a surge tank; operating means which comprises a pipe line for conducting fluid under pressure to the booster cylinders, connections from the main cylinder to the surge tank including a valve which automatically opens when the fluid enters the booster cylinders, a branch from said pipe line to the main cylinder, a valve in said branch, and means for opening said valve to admit fluid under pressure directly to the main cylinder, said connections then permitting said fluid to close said first-mentioned valve.

2. In a hydraulic press mechanism having main, booster, and push-back cylinders, a press ram operated thereby and a surge tank; operating means which comprises a pipe line for conducting fluid under pressure to the booster cylinders, connections from the main cylinder to the surge tank including a valve which automatically opens when the fluidenters the booster cylinders, and a second valve which opens when the pressure in said pipe line reaches a predetermined point and admits fluid under pressure from said pipe line directly to the main cylinder, said connections then permitting said fluid to close said first-mentioned valve.

3. In a hydraulic press mechanism having main, booster, and push-back cylinders, a press ram operated thereby and a surge tank; operating means which comprises a pipe line for conducting fluid under pressure to the booster cylinders, connections from the main cylinder to the surge tank including a valve which automatically opens when the fluid enters the booster cylinders,

inder, said connections then permitting said fluid to close said first-mentioned valve, and

means for admitting fluid under pressure to the push-back cylinders to return the press ram.

4. In a hydraulic press mechanism having main, booster, and push-back cylinders, a press ram operated thereby and .a surge tank; operating means which comprises a pipe line for conducting fluid under pressure to the booster cylinders, connections from the main cylinder to the surge tank including a valve which automatically opens when the fluid enters the booster cylinders, a second valve which opens when the pressure in said pipe line reaches a predetermined point and admits fluid under pressure from said pipe line directly to the main cylinder, said connections then permitting said fluid to close said first-mentioned valve, a pipe line for admitting fluid under pres sure to the push-back cylinders to return the press ram,- and means for opening the firstnamed valve during said return.

5. In a hydraulic press mechanism having main, booster, and push-back cylinders, a press ram operated thereby and a surge tank; operating means which comprises a pipe line for conducting fluid under pressure to the booster cylinders, connections from the main cylinder to the surge tank including a valve which automatically opens when the fluid enters the booster cylinder, a second valve which opens when the pressure in said pipe line reaches a predetermined point and admits fluid under pressure from said pipe line directly to the main cylinder, said connections then permitting said fluid to close said first-mentioned valve, a pipe line for admitting fluid under pressure to the pushback cylinders to return the press ram, and a branch therefrom communicating with said first named valve whereby it will be opened by fluid under pressure.

6. In a hydraulic press mechanism having main, booster, and push-back cylinders, a press ram operated. thereby and a surge tank: operating means which comprises a pipe line for conducting fluid under pressure to the booster cylinders, connections from the main cylinder to the surge tank including a valve which automatically opens when the fluid enters the booster cylinders, a second valve which opens when the pressure in said pipe line reaches a predetermined point and admits fluid under pressure from said pipe line directly to the main cylinder, which fluid then closes said first-mentioned valve, a pipe line for admitting fluid under pressure to the push-back cylinders to return the press ram, and separate connections from said pipe line permitting fluid to flow from the main cylinder and booster cyllnders respectively to the surge tank during the return movement.

7 In a" hydraulic press mechanism having main, booster, and push-back cylinders, a press rain operated thereby, and a surge tank; operating means which comprises a pipe line for conducting fluid under pressure to the booster cylinders, a connection therefrom directly to the main cylinder, a connection from the main cylinder to the surge tank, a separate connection from the pipe line to the surge tank which permits fluid to flow from the booster cylinders to the surge tank, and a valve in each of the threeconnections enumerated.

8. In a hydraulic press mechanism having main, booster, and push-back cylinders, a press ram operated thereby, a surge tank, and two pipe lines adapted to receive fluid under pressure; operating mechanism com-- prising connections between the booster cylinders and the surge tank, a valve insaid connections, connections between the main cylinder and the surge tank, a valve therein, and means whereby fluid under pressure in one of said pipe lines will open both valves.

9. In a hydraulic press mechanism having main, booster, and push-back cylinders, a press ram operated thereby, a sur e tank, and two pipe lines adaptedto receive fluid under pressure; operating mechanism com prising connections between the booster cylinders and the surge tank, a valve in said connections, connections between the main cylinder and the surge tank, a valve therein, means whereby fluid under pressure in one of said pipe lines will open both valves, connections between the other pipe line and the main cylinder, a valve therein, and means whereby this valve will open only when a predetermined pressure has been reached in press ram operated thereby, a surge tank,

and two pipe lines adapted to receive fluid under pressure; valve mechanism com rising a casing having three chambers of which the first chamber communicates with one pipe line and the booster cylinders, the second chamber with the surge tank, and the third chamber with the other pipe line and the push-back cylinders, a single valve member controlling communication between the second chamber and the first and third chambers alternately, the fluid under pressure in the first pipe line moving said valve memher to permit fluld from the push-backcylinders to return to the surge tank during the press stroke of the ram, and the fluid under pressure in the second pipe line moving said valve member to permit fluid from the booster cylinders to return to the surge tank during the return stroke of the press ram.

11. In a hydraulic press mechanism having main, booster and push-back cylinders, a press ram operated thereby and a surge tank; operating means which comprises a pipe line for conducting fluid under pressure to the booster cylinders, connections from the main cylinder to the surge tank including a valve which automatically opens when the fluid enters the booster cylinders, a branch from said pipe line to the main cylinder, a valve in said branch, the movement of the valve in one direction being controlled by the fluid under pressure in the pipe line, and the movement in the other direction being controlled by the movement of the press ram.

In testimony whereof, I have hereunto subscribed my name.

I/VALTER ERNST. 

